The production of finished stone products, for example facing stone, stone tiles, and other thin, flat stone configurations, begins in a quarry where large blocks of stone are separated from the earth using a variety of techniques, some dating back to antiquity. Once quarried, large blocks of stone must be further processed, typically very close to the point where the stone was quarried. This is primarily because of the difficulty in moving large blocks of stone as well as the noise, dirt, and waste produced by the post quarrying processes.
One process typically used to produce thin, flat, stone products is slab sawing. Several different techniques are known and used for slabbing large stone blocks. One is gang sawing wherein a gang of spaced-apart fixed saw blades is mounted in a frame which is reciprocally moved across a stone block. Upon completion of the gang sawing process, parallel slabs of stone are produced. Diamond covered belts or cables may replace the saw blades.
Gang saws have at least two disadvantages. First, the thickness of the stone slabs produced is fixed by the design of the saw frame. Consequently, producing different thickness slabs is problematic. The second disadvantage of a gang saw is speed. Gang saws are significantly slower than rotary blade slabbing saws.
Rotary blade slabbing saws are not unlike radial arm saws well known in the woodworking arts. These saws are typically gantry saws that move on rails over a series of large stone blocks, slabbing each block as required. Having diamond tipped blades as large as 12 feet in diameter, these monster saws cut slice after slice off a stone block. Modern versions of these saws may be computer-controlled and laser guided. A modern, high-tech example of such a saw is the Eagle II traveling bridge diamond saw manufactured by Park Industries of St. Cloud, Minn.
Regardless of how new the technology incorporated, rotary blade slabbing saws have one severe limitation. At the completion of each cutting pass, a severed stone slab remains adjacent the saw blade. If the severed slab topples backward (i.e., towards the saw blade), or perhaps worse, the previously-cut, vertically standing groups of slabs collectively fall backward like dominoes into the blade, the expensive blade is invariably damaged, possibly beyond repair, resulting in lost time and cost. Because the saw blades often cost several thousand dollars each, this is a significant problem. Even if blade damage is avoided, the slabs may subsequently be re-sawed thereby ruining them.
Moreover, slab sawing operations are often performed at night, the day typically being spent in the actual quarrying operations. Once the stone blocks are positioned and the slab saws are set up, slab sawing requires little operator intervention. Except for the aforementioned potential toppling problem, slab saws may therefore run virtually unattended.
Two approaches to the aforementioned problem have heretofore been offered. First, the slab saws may be adjusted to stop their cutting pass slightly short of the end of the slab, thereby avoiding complete severance of the slabs. This leaves the slabs still connected to their adjoining slabs and the problem of a slab tipping into the saw blade is therefore avoided. Unfortunately, at some point in time, the cuts must be completed. This is a tricky operation at best; a slight misalignment of the saw blade compared to the original saw kerf can ruin one or more slabs. This operation is also very labor intensive requiring an expert saw operator to successfully complete each cut.
Another approach to the potential blade damage problem is by keeping a skeleton crew of attendants on duty during slab sawing operations. As the saw nears completion of a cut, the operator stands by and manually exerts force on the nearly severed slab to ensure that it moves away from the blade at the completion of the cut. As previously mentioned, slab sawing operations are typically performed at night near the quarry site. Such sites are remote and are typically the epitome of inhospitality. The large amounts of water used during the sawing and other quarrying operations create a virtual quagmire. The saws are extremely noisy and the sites are rarely well lighted. In addition to the undesirable environment, being in close proximity to the saw blades is dangerous. Quarry operators report dismal records of success with this approach to protecting the saw blades.
It would, therefore, be advantageous to provide an unattended, foolproof, automatic apparatus to ensure that at the completion of the sawing operation, a severed stone slab tilt or fall away from the saw blade.